Castrol syntrax 80/90w gl4, it's about the best cost wise and performance in the gearbox, don't use gl5 or higher in the gearbox as the syncros will crunch, and the diffs can use the same as the gearbox, to change the rear diff, transfer box and gearbox you will need 7-8litres of oil.
As has been stated, Castrol Syntrax 75/90W or 80/90W GL4.
You will need 4.2 litres for the gearbox, 1.5 litres for the transfer case and 1 litre for the rear diff. So, all up 6.7 litres. From memory this only comes in 1 litre and 5 litre bottles.
Just to clear things up.
The Castrol Syntrax 75/90W IS NOT for use with the rear Nismo LSD, it is for standard Viscous Diff.
You can however use the Castrol in the Modena front diff, because it is worm drive, not plated.